The invention relates to an inkjet printhead comprising two substantially closed ink chambers separated by a wall, each of the chambers comprising an electro-mechanical converter, where actuation of the converter corresponding to the first chamber of said printhead will lead to a volume change in the second chamber due to cross-talk. The invention also relates to an inkjet printer comprising this printhead.
A printhead of this kind is known from U.S. Pat. No. 6,161,925. This printhead comprises a row of elongated ink chambers, also referred to as ink ducts, which by application of a machining technique have been fitted inside a so-called duct plate (element 12, see FIG. 1 of the corresponding patent). The chambers are covered by a compliant foil at the top, making them substantially closed. Furthermore, each chamber comprises an inlet opening for feeding ink into the chamber and an outlet opening (nozzle) from where individual ink drops may be ejected from each of the chambers. To this end, each of the chambers is operationally connected to a piezo-electric type electro-mechanical converter. By actuating a converter, it will expand or shrink. This movement is signaled to the chamber corresponding to this converter through the compliant foil, said chamber thus experiencing a sudden volume change. As a result, pressure waves are generated inside the chamber, under the influence of which a drop of ink may be ejected from the chamber.
In the known printhead, the converters are grouped into individual blocks, where each block comprises a carrier element on which two converters have been fitted to generate pressure waves in their corresponding chambers, as well as a support element resting on the foil at the level of the wall between the two chambers. The blocks have been fitted to a rear plate having high rigidity in a direction parallel to the chambers, and low rigidity in a direction perpendicular to the chambers. This construction is designed to prevent cross-talk. Cross-talk is the phenomenon caused by actuation of the converter corresponding to a certain chamber, producing a volume change in an adjacent chamber. This (undesired) volume change may lead to pressure waves which may adversely affect the drop ejection process in this adjacent chamber. However, in this known printhead, cross-talk is still a common occurrence. Within one block, for example, there may be a moderate power closure so that deformation of the one converter will almost certainly lead to deformation of the other converter and therefore also to a volume change in the adjacent duct. Another possible or additional cause of volume change in the adjacent chamber is that due to actuation of the converter and the associated pressure waves, the duct plate is locally stretched into a direction parallel to the direction in which the piezo-electric elements extend. This causes cross-talk between two ducts corresponding to separate blocks to also occur in the case of the known printhead.